Draft Response to the FCC NPRM 15-138

DCN 18-15-0072-00-0000

Draft Response to the FCC NPRM 15-138

Draft r0

Suitability of the Existing Rules in section 15.255 to the 6471GHz Band. We are proposing to extend the technical requirements in section 15.255 to encompass the 5771GHz band. As we discuss in detail below, we believe that the existing technical rules in the 5764GHz band can successfully apply to the proposed 6471GHz adjacent band, with certain minor adjustments. In addition, we seek comment on certain aspects of the rules to further the growth and development of these devices without increasing the potential for harmful interference to authorized users in these bands. We examine the pertinent rules in section 15.255 below.

304, 305, 306 address to “Operation On Board Aircraft”: As such, we believe that the prohibition on operation on board aircraft may be revisited at the present time.[1] We therefore seek comment on this issue.

We request technical studies and interference analyses demonstrating whether transmissions in the 57-71GHz band should be permitted on aircraft. Such operations may include applications in the 5771GHz band that support enhancement of inflight communications service offerings by airlines to meet the increasing consumer demand for broadband connectivity on aircraft.RESPONSE:Based on the interference analysis using WiGig radios operating in the 57-64 GHz, we believe there should be no interference to radio astronomy operation or to the satellites from such operation aboard aircraft. We have, however, not yet conducted similar analysis in the 64-71 GHz band. We will provide the results of the analysis as soon as it is completed.

Is it possible to limit unlicensed device operation on aircraft to a narrower portion of the 57-64 GHz band to minimize impact to the radio astronomy observations?If so, should we (FCC) consider such a limitation?RESPONSE: It is difficult to limit operation to a narrower portion of the band while on an aircraft, since devices may not be aware of contextual information. Given the propagation characteristics of these frequency bands such as extremely limited propagation through objects, we do not believe limiting operation onboard aircraft to a narrower portion of this band to be necessary. Further study is required to determine whether the operation in 64-71 GHz will cause interference to radio astronomy operations.Additional channels afforded by the additional spectrum, 64-71 GHzmay be utilized in channel bonding mode for improved throughput performance and user experience for on-board applications.

We do not recommend that commission put such restrictions of the use on the new spectrum band till interference to radio astronomy operations is demonstrated. However, we would like to emphasize that 57-64 GHz WiGig radios are already being integrated in some of the mobile consumer products, and removing above restriction in this band is our most immediate priority.

307 addresses “Fixed Field Disturbance Sensor Operation”:

RESPONSE: We should be ok with this?

308, 309, 310address Emission Limits: Commission proposes to keep the existing limits (same as 57-64 GHz)

Commission seeks comment on these tentative conclusions.RESPONSE: We agree with the commission to apply the same emission limits to the 64-71 GHz spectrum band as they are. This would allow manufacturers to apply the same uniform emissions across the 57-71 GHz band and drive economy of scale that will spur broad based user adoption technologies operating in this band. Further, as the commission noted, these same power levels would allow longer ranges in the extended band due to the properties of the spectrum.

311 addresses Spurious Emissions:Section 15.255(c) restricts spurious emissions to a power density limit of 90 pW/cm2 at a distance of 3 meters for frequencies between 40 and 200GHz,[2] and to the general limit for intentional radiators in section 15.209 for frequencies below 40GHz.[3] We propose to apply the same spurious emissions limits to transmitters operating in the proposed 6471GHz band.

Commission seeks comment on this proposal.RESPONSE: We agree with the commission to apply the same spurious emission limits to the extended spectrum band as in the existing 57-64 GHz band.

312 addressesPubliclyAccessible Coordination Channel: Agree to remove restrictions on coordination channel (57.00-57.05 GHz).RESPONSE: We agree with commission’s proposal to remove restrictions on the coordination channel in the 57.00-57.05 GHZ band.

313 adresses Conducted Transmitter Output Power as per Part 15.255: RESPONSE: We propose that commission remove arbitrary limits on conducted power, and only require limits on EIRP. This would provide added implementation flexibility for different applications.The rules may still require minimum antenna gain for outdoor point-to-point applications.

314 addresses Frequency Stability:RESPONSE: We agree with the commission to apply the same rules to 64-71 GHz as for 57-64 GHz.

315 addressesColocation of separatelyauthorized transmitters:RESPONSE: We agree to apply same rules as 57-64 GHz (15.255)

316 We seek comment on the various sharing analysis framework among fixed, mobile and satellite systems, as well as between active and passive services in the millimeter bands. Specifically, we request technical information on transmitter and receiver characteristics including peak and average transmit power and antenna performance, operational assumptions including antenna orientation and practical use case of transmitters and receivers, and appropriate propagation models for each sharing analysis that would assist in evaluating interference potential including aggregate effects as applicable.RESPONSE: TBD

318 Specifically, we request information on relevant research as we address two topics: 1) measurement techniques to verify that devices meet limits on peak EIRP and out-of-band emissions (OOBE), and 2) demonstration of compliance with respect to the Commission’s rules on RF exposure.

319 EIRP Measurement: RESPONSE: TBD

320 Out-of-Band and Spurious Emissions Measurement. RESPONSE: TBD

321 – 324 RF Exposure Compliance. RESPONSE: TBD

[1] We are not revisiting the prohibition for operation on board satellites in 47 C.F.R. § 15.255(a)(1) at this time.

[2] A power density of 90 pW/cm2 is equivalent to a field strength of 18430 µV/m or 85.3 dBµV/m; and to an EIRP of 10 dBm. Power density (PD), EIRP and field strength (E) are readily converted through the following formulae: PD=E2/120(Pi)=EIRP / (4 Pi D2), where D is the separation distance in meters, provided measurements are performed in the far field.

[3] 47 C.F.R. § 15.255(c); 47 C.F.R. § 15.209(a). The limit for emissions above 960MHz is 500µV/m (54 dBµV/m) as measured at 3meters, or 41.3dBm EIRP.